There used to be a real status-y thing about having a 212 phone number, but over the past decade, with the surge of cell numbers, it is no longer necessary to have a 212 prefix and still be recognized as a New Yorker, In fact, when it come to cell phones only those who have ported their home numbers to a cell have a mobile 212. (I'm not sure this prefix was ever issued directly to mobiles.)
917, 646, and 347 are now all recognizable New York area prefixes.
Don't make this decision more difficult than it really is. If you want to change your number, then do a mass mailing of your new resumes once you have done so. People change phone numbers and e-mail addresses all the time, and somehow survive!
Good luck!
I actually think having a New York number is important if you are trying to establish yourself in New York City - there is a hierarchy of the New York numbers, but having a 212 number is sort of a status symbol in some circles.
If you are trying to establish yourself in New York, you might want to look into it - it does look like you have been in NYC for awhile and establishing yourself as a New Yorker.
Good luck on the move to New York.